The driver of the sport-utility vehicle (SUV), a 26-year-old Austrian of Bosnian origin known to police for domestic violence, was detained. Police said there was no reason to suspect any terrorist motive and they believed the man was suffering family problems.

Eyewitnesses cited by the public broadcaster ORF said the vehicle had been travelling at about 100 kph (62 mph). ORF said no explosives had been found in the car.

"We can now absolutely rule out an extremist, religious or political background," Josef Klamminger, head of the police force of the province of Styria, told reporters.

"He has (previously) appeared ready to use violence," Klamminger said. The man also stabbed two people after jumping out of the crashed car.

When asked whether the man had any psychological problems, a Graz police official, Kurt Kemeter, said: "Of course there would have been problems".

He said the man, a truck driver who is married and has two children, gave himself up to the police after the incident.

Three children were among the injured. Six people were in a critical condition, according to emergency services. More than 60 police, about 80 ambulances and a rescue helicopter were mobilised.

Pictures on local media websites showed a green SUV with a severely damaged front and smashed broken lights, and a scarf hanging from it.